SHANGHAI 
Defending champion Novak Djokovic advanced to the final of the Shanghai Masters on Saturday with a 6-2, 7-5 win over Jo-Wilfried Tsonga, putting him in position to win back-to-back titles in China for the second straight year.

The top-seeded Serb extended his winning streak in China to 19 straight matches dating back to last year when he won the China Open in Beijing and then Shanghai. He successfully defended his China Open title last week, and will try to do the same in Shanghai on Sunday.

"It's important for me to get into another final," Djokovic said. "(My serving) was very controlled, very efficient. ... I was trying to open up the court and move him around."

Djokovic lost his No. 1 ranking to Rafael Nadal this week, although beat the Spaniard in the Beijing final. He could come up against Nadal again on Sunday, as the Spaniard plays Juan Martin del Potro in the other semifinal later.

Djokovic raced out to a 3-0 lead after only seven minutes against Tsonga, who came out looking flat and misfiring wildly at times on his groundstrokes and volleys.

However, Djokovic then lost his temper in the second set when serving at 4-2, yelling angrily at the chair umpire after two disputed calls. Tsonga twice challenged late calls that went against him - and both times the Hawk-Eye camera replay showed the balls had clipped the line. The umpire awarded both points to the Frenchman, prompting a furious reaction from Djokovic who thought the points should have been replayed.

"Twice I was on the ball, twice you take the point away from me," Djokovic yelled. "Focus!"

Tsonga managed to break the rattled Serb to get back on serve at 4-3, but his comeback was short-lived as another error-strewn game allowed Djokovic to break him at 6-5 to close out the match.

The Frenchman, who missed several months this year with a knee injury, still boosted his chances of reaching the season-ending ATP finals, moving into position to claim the last spot in the eight-man field for the tournament in London, with three weeks left to play in the season.

"I have to play if I want to go," Tsonga said. "I just have to play and try to win as much as possible."